What is a goal of an access control system regarding user access verification?

An access control system's primary goal regarding user access verification is to ensure that permissions are checked on every access attempt. This is crucial for maintaining security, as it prevents unauthorized access to resources or sensitive data. By verifying permissions each time a user tries to access a system or resource, the access control system can enforce policies that dictate who is allowed to access what, thereby greatly reducing the risks of breaches and ensuring compliance with security regulations.

This ongoing verification process confirms that the user still has the appropriate permissions, especially in environments where roles and access needs might change frequently. Each access check serves as a safeguard against potential security threats, ensuring that even if a user's role were to change or if their credentials were compromised, unauthorized access can still be blocked effectively.

The other choices do not align with best practices for access control. Indefinitely verifying users is impractical and could hinder user experience, while providing unrestricted access after initial verification poses a significant security risk. Allowing access based on previous usage is also inadequate, as it does not adapt to changes in permissions that might occur over time. Therefore, checking permissions on every access remains the most effective approach for an access control system.